Merge pull request #74 from stefanomondino/documentation

Documentation for bindTo

Author: stefanomondino

Readme.md

@@ -58,6 +58,24 @@ Now when the button is pressed, the action is executed. The button's `enabled` s
 
 If you'd like to use `Action` to do a complex operation such as file download with download progress report (to update progress bar in the UI for example) you'd use `Action<Void, Int>` instead of `CocoaAction`. Out of the box `CocoaAction` can't emit progress values, your own `Action<Void, Int>` will do that. For details refer to [this article](http://www.sm-cloud.com/rxswift-action/).
 
+If your scenario involves many buttons that needs to trigger the same `Action` providing different input, you can use `bindTo` on each `UIButton` with a closure that returns correct input.
+
+```swift
+let button1 = UIButton()
+let button2 = UIButton()
+
+let action = Action<String,String> { input in
+  print(input)
+  return .just(input)
+}
+button1.rx.bindTo(action) {_ in return "Hello"}
+button2.rx.bindTo(action) {_ in return "Goodbye"}
+```
+
+`button1` and `button2` are sharing the same `Action`, but they are feeding it with different input (`Hello` and `Goodbye` that will be printed for corresponding tap).
+
+A more complex use case can be a single action related to a `UIViewController` that manages your navigation, error handling and loading state. With this approach, you can have as many `UIButton`s (or `UIBarButtonItem`s) as you want and subscribe to `executing`, `errors` and `elements` once and in a single common place.
+
 There's also a really cool extension on `UIAlertAction`, used by [`UIAlertController`](http://ashfurrow.com/blog/uialertviewcontroller-example/). One catch: because of the limitations of that class, you can't instantiate it with the normal initializer. Instead, call this class method:
 
 ```swift
@@ -88,7 +106,7 @@ github "RxSwiftCommunity/Action" ~> 2.1.1
 then run
 
 ```
-$ carthage update 
+$ carthage update
 ```
 
 Thanks